Dera Sacha Sauda Gurmeet Ram Rahim Singh, who is at loggerheads with the Sikh clergy, escaped unhurt in a blast in his motorcade near Karnak in Haryana on Saturday. However, 11 persons, including six security men, were injured in the blast.

Unidentified persons from a truck parked on a highway, on which the Dera chief's cavalcade was passing, threw a tyre stuffed with explosives at one of the cars, which burst into flames, Additional Director General of Police V B Singh told PTI.

The incident occurred near Nilokheri in Karnal district, when the sect head was returning to Delhi after appearing in a court in Ambala.

"A team of forensic experts from Madhuban (Karnal) has collected the samples from the site of the blast," said Karnal Deputy Commissioner B S Malik.

'Investigations are on and the actual position could be known only after receiving the report of the forensic experts," Malik said.

The police fired in the air and resorted to lathi charge to disperse the Dera followers, who blocked the busy national highway after the incident. The protestors pelted stones at the police and the vehicle of the Deputy Commissioner was damaged.

Haryana Police rounded up two persons, including the driver of the truck, Singh said.

The ADGP said forensic experts have picked up some pieces of the tyre used in the blast and other material. A detonator was also found from the spot, he said.

"We are investigating the matter, including the claim of the two injured regarding the blast, from all angles," Singh said.

Haryana Home Secretary K S Bhoria, who did not rule out a planned attack on the Dera chief, said Haryana and neighbouring states were put on high alert and the authorities were monitoring the situation closely.

He said the government was also keeping a close watch on the Dera followers, who had blocked the national highway number one, near Karnal, Kurukshetra and Ambala after after the incident.

A large number of Dera followers blocked the Delhi Ambala National Highway after the incident stranding vehicles, Singh said, adding reinforcement from neighbouring districts has been requisitioned to ensure peace as the situation is tense but under control.

The sect chief hit the headlines in May last year after he appeared in a dress similar to that of 10th Guru Gobind Singh, leading to protests from the Sikhs at various place in Punjab, Haryana and other states.

Besides, he was also among the accused in three criminal cases -- two murders and an alleged molestation of a woman disciple.